Supramolecular Nanotube Architectures Based on Amphiphilic Molecules

Tuning the dimensionality of semiconducting nanostructures by self-assembled tetraphenylethylene substituted corroles

Controlling the dimensionality of nanostructures made from self-assembled macrocyclic systems is tedious because they attain thermodynamic stability through the extended π-conjugated structure. Mainly, corrole-based macrocycles are challenging as they form structures that make it difficult to grow hierarchical assemblies. Herein, three tetraphenylethylene (TPE) appended corroles (1-TPE-Cor, 2-TPE-Cor and 3-TPE-Cor) were developed by substituting one, two or three TPEs at the meso phenyl positions of corroles. Detailed investigations revealed that each TPE substituent influences the molecule's planarity, resulting in significant variations in optical, self-assembly, and electronic properties in the three derivatives. One-dimensional (1D) nanotubes were observed through π-π stacking for 1-TPE-Cor, while 2D nanosheets and nanospheres were seen for 2-TPE-Cor and 3-TPE-Cor. Consequently, the electrical conductivity of 1D nanotubes is 10 times higher than for the 2D and 0D nanostructures. Each TPE substituent on corroles affects their aggregation dynamics and electronic properties, and this study promotes novel corrole-based macrocyclic groups, apart from porphyrin and phthalocyanine, utilizing supramolecular interactions, paving the way to diversification in the field of electronics.

Orderly Arranged Cubic Quantum Dots along Supramolecular Templates of Naphthalenediimide Aggregates

Precise control of assembled structures of quantum dots (QDs) is crucial for realizing the desired photophysical properties, but this remains challenging. Especially, the one-dimensional (1D) control is rare due to the nearly isotropic nature of QDs. Herein, we propose a novel strategy for controlling the 1D-arrangement range of cubic perovskite QDs in solution based on the morphological modification of a supramolecular polymer (SP) template. The original template with a short and tangled fibrous structure is prepared in a low-polarity solvent mixture via self-assembly of a naphthalenediimide-functionalized cholesterol derivative with an adhesion group for QDs. Mixing this template with QDs leads to the co-aggregation into short-range 1D-arrays of QDs on the templates. Notably, subsequent heating and cooling of the co-aggregate solution forms longer-range 1D-arrays of QDs with lateral growth, where arranged QDs are sandwiched between reconstructed SP templates. Furthermore, the longer-range 1D-array of QDs is achieved via an alternative route involving the pre-organization of templates into longer and dispersed fibers by heating and cooling of the original template, succeeded by co-assembly with QDs. Finally, we reveal continuous fluorescence resonance energy transfer between 1D-arranged QDs by an in-depth analysis of the photoluminescence decay curves.

Stereoisomerism-dependent gelation and crystal structures of glycosylated N-methylbromomaleimide-based supramolecular hydrogels

In this study, we developed glycosylated N-methylbromomaleimide-based supramolecular hydrogels exhibiting colour change along with gel-sol transition and found that the stereoisomerism of the saccharide residue affects their gelation ability. Single-crystal X-ray diffraction analysis revealed the molecular packing and hydrogen-bonding networks contributed by the saccharide residues. Interestingly, it was found that water molecules were incorporated into the hydrogen-bonding network in the crystals of the compounds that showed gelation ability.

Photoinduced Electron Transfer System from Cesium Lead Bromide Quantum Dots to Naphthalenediimide Supramolecular Polymers

Supramolecular polymers (SPs) formed via the stacking of π-conjugated molecules are attractive nanomaterials because of their potential optoelectronic properties derived from the non-covalent interaction between the π-skeletons. Especially, SPs possessing naphthalenediimide (NDI) core units can act as superior electron acceptors due to their deep lowest unoccupied molecular orbital (LUMO). Interaction of such SP with electron donors can realize a charge transfer system, but this has not been established. Herein, we report a photoinduced electron transfer system from cesium lead bromide quantum dot (QD) as an electron donor to SP composed of cholesterol-functionalized NDI derivatives. The supramolecular polymerization in a non-polar solvent was analyzed in detail via microscopic and spectroscopic analyses. Upon mixing the SP with QDs, the photoluminescence intensity and lifetime of QDs decreased significantly, indicating efficient photoinduced electron transfer from QD to SP.

Monomers Versus Prenucleation Clusters En Route to Polymorphism of Supramolecular Polymers

Polymorphism in supramolecular polymers is strongly correlated with the polymerization pathways underlying their formation. To effectively control emerging polymorphs, a comprehensive understanding of nucleation pathways and mechanisms is essential. Herein, a coronene-dipeptide conjugate (Cr-o-FFOEt) is introduced and its self-assembly into two different stable 1D supramolecular polymorphs (Agg 1 and 2f) is observed in the same solvent composition (water/THF, 7:3 v/v) and same concentration at room temperature, following two competitive self-assembly pathways. The difference in the mode of solvent addition triggers the two self-assembly pathways. Furthermore, the isolated intermediate Agg 2i is found to transform into Agg 1 or Agg 2f under controlled experimental conditions. The supramolecular aggregates of Cr-o-FFOEt are thoroughly examined with the help of optical, chiroptical, and morphological techniques to understand the subtle difference in choosing the self-assembling pathways. The studies reveal that the nanotube formation of Agg 1 follows a classical nucleation-elongation supramolecular polymerization mechanism (involving monomers). In contrast, the helical fibers of Agg 2f are formed by the involvement of preorganized oligomers (nonclassical process). The observation highlights the underappreciated role of prenucleation clusters in pathway complexity and polymorphism of supramolecular 1D polymers.

Rational design of self-assembling ultrashort peptides for the shape- and size-tunable synthesis of metal nanostructures

Peptides have attracted great interest as platforms for the design of nanocomposite hydrogels due to their distinct bioactivity, biofunctionality and biocompatibility. Previously, we have reported on a family of peptides that self-assembled to form stabilised three-dimensional hydrogel networks, displaying potent antimicrobial activity. In this paper, we report on the use of these hydrogelator sequences and their analogues as stabilisers and growth controllers to synthesise anisotropic gold nanoparticles (AuNPs) of different sizes and shapes. In particular, hollow spherical nanoparticles were obtained for HG2.81-AuNPs, whereas hexagonal nanoparticles were observed for TOH_1N-AuNPs and PentaOH-AuNPs in their respective hydrogel networks. The PentaOH-AuNPs' hydrogel exhibited excellent results with high antimicrobial potency against Staphylococcus aureus and Pseudomonas aeruginosa ATCC 27853 and negligible cytotoxicity. On the other hand, TOH_1N-AuNPs showed no antibacterial activity and no cytotoxicity, demonstrating the versatility of these peptides. This work gives credence towards the development of these materials towards further applications such as in tissue culture technology and wound dressing materials.

Self-Assembled Bolaamphiphile-Based Organic Nanotubes as Efficient Cu(II) Ion Adsorbents

Self-assembled organic nanotubes (ONTs) have been actively examined for various applications such as chemical separations and catalysis owing to their well-defined tubular nanostructures with distinct chemical environments at the wall and internal/external surfaces. Adsorption of heavy metal ions onto ONTs plays an essential role in many of these applications but has rarely been assessed quantitatively. Herein, we investigated interactions between Cu2+ and single-/quadruple-wall bolaamphiphile-based ONTs having inner carboxyl groups with different inner diameters, COOH-ONT10nm and COOH-ONT20nm. We first examined the effects of Cu2+ on their nanotubular structures using SAXS, STEM, and AFM. COOH-ONT10nm was stable in aqueous Cu2+ solution in contrast to COOH-ONT20nm owing to the presence of polyglycine-II-type hydrogen bonding networks within its wall. Subsequently, we studied the Cu2+ adsorption behavior of COOH-ONT10nm by monitoring the concentration of unbound Cu2+ using linear sweep anodic stripping voltammetry. The Cu2+ adsorption was quick, attributable to efficient Cu2+ partitioning through the open ends of the ONT, followed by fast Cu2+ diffusion in the uniform, relatively large nanochannel. More importantly, the Cu2+ adsorption capacity and affinity of COOH-ONT10nm were measured under different pH conditions using the Langmuir adsorption model. The adsorption capacity was similar at the pH range examined, showing the participation of approximately 25% of the inner carboxyl groups in the adsorption. The adsorption affinity increased with pH, indicating the essential role of the deprotonated carboxyl groups in Cu2+ adsorption. Most interestingly, the Langmuir adsorption constant was significantly higher than those of previously reported synthetic adsorbents and planar monolayer based on carboxyl binding sites. The high Cu2+ affinity of the ONT was attributable to the highly dense binding sites on the well-defined nanoscale concave structure of the inner channel. These results provide a valuable guideline for designing self-assembled nanomaterials for efficient chemical separations, detection, and catalysis.

Morphology Transition of Tripeptides from Porous Spherical to Rod-like Nanostructures for Small-Molecule Adsorption

Peptides possess a remarkable propensity to adopt distinct morphologies, ranging from simple aggregates to complex structures such as fibrils and nanotubes. Morphology transformation in peptides is intricately linked to the physicochemical properties of peptides and external factors such as pH, temperature, and solvent conditions. Thus, it is more complex. Herein, we present four tripeptides, Boc-LVL-OMe (LVL), Boc-IVI-OMe (IVI), Boc-LVI-OMe (LVI), and Boc-IVL-OMe (IVL), which undergo direct morphological transformation (except for Boc-IVL-OMe) with time. The morphological transformation from nanospheres to rod-like structures was verified using electron microscopic studies (FESEM and FETEM). Dynamic light scattering (DLS) studies further supported the results and are in good agreement with the observed phenomena. CD and FTIR studies were conducted for conformational analysis, suggesting a mixture of unordered and β-sheet conformations. Except for IVL, all other tripeptides are mesoporous and adsorb N2 gas. Another important application of our designed tripeptides is that they can encapsulate the low-molecular-weight biologically active drug molecule curcumin. The encapsulation property and its sustained release after being treated with salt were studied by using fluorescence spectroscopy and fluorescence microscopy. Therefore, understanding the dynamics of these interactions and their impact on peptide morphology is crucial for harnessing their functional diversity in applications, such as drug delivery, tissue engineering, and nanotechnology.

The structural and functional impacts of rationally designed cyclic peptides on self-assembly-mediated functionality

Compared with their linear counterparts, cyclic peptides, characterized by their unique topologies, offer superior stability and enhanced functionality. In this review article, the rational design of cyclic peptide primary structures and their significant influence on self-assembly processes and functional capabilities are comprehensively reviewed. We emphasize how strategically modifying amino acid sequences and ring sizes critically dictate the formation and properties of peptide nanotubes (PNTs) and complex assemblies, such as rotaxanes. Adjusting the number of amino acid residues and side chains allows researchers to tailor the diameter, surface properties, and functions of PNTs precisely. In addition, we discuss the complex host-guest chemistry of cyclic peptides and their ability to form rotaxanes, highlighting their potential in the development of mechanically interlocked structures with novel functionalities. Moreover, the critical role of computational methods for accurately predicting the solution structures of cyclic peptides is also highlighted, as it enables the design of novel peptides with tailored properties for a range of applications. These insights set the stage for groundbreaking advances in nanotechnology, drug delivery, and materials science, driven by the strategic design of cyclic peptide primary structures.

Crystallographic models of ribbons and ribbon-based J-aggregate nanotubes from the geometry of tube ends

Self-assembly into tubular structures typically proceeds by helical winding of ribbon intermediates, however, only the central parts of the tubes, that retain no information on the ribbon geometry, have received attention so far. We propose the procedure of establishing the crystal structure of ribbons and ribbon-based tubes on the basis of crystallographic analysis of the tube-end geometry, where the terminal parts of the ribbons fold and form characteristic mono/bilayer polygonal shapes. The terminal parts of flattened J-aggregate nanotubes of trimethine cyanine dye were clearly resolved in electron microscopy and atomic force microscopy images, and the original parallelogram shape of ribbons was reconstructed and interpreted as a two-dimensional [1-10]/[010] facetted crystal with inclined molecular π-stacks parallel to the long ribbon side. The back-reconstructed molecular orientations in a tube wall tend to be close to the tube normal. A two-stage "nucleation and growth" type model of the ribbon to tube transition is proposed that takes into account the established ribbon mechanical asymmetry. The model includes closure of the single ribbon loop as a nucleation event and explains, mostly observed in experiments, nearly rectangular shapes of tubes by the transition kinetics. Due to its universal character, the suggested approach can be applied to any ribbon-based tubes, regardless of their chemical composition.

Self-Assembly of Photoresponsive Nano Scrolls Produced by Exfoliation of Layered TaWO6

Novel photoresponsive nano scrolls of tantalotungstate intercalated with C3F7-Azo+ were synthesized by guest-guest ion exchange. Physicochemical characterization utilizing X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) verified the successful synthesis of spiral nano scrolls. XRD and UV data evidenced aggregated conformations of C3F7-Azo+ with end-to-end J-type configurations between the tantalum tungstate layers. The nano scrolls exhibited reversible trans-cis photoisomerization under ultraviolet and visible light irradiation at 365 and 440 nm, respectively, while the basal spacing accompanying the photoresponse was reversibly changed. Overall, photofunctional tantalum tungstate nano scrolls have promising applications in optoelectronic devices.

Spontaneous nanotube formation of an asymmetric glycolipid

Over the past decades, advances in lipid nanotechnology have shown that self-assembled lipid structures providing ease of preparation, chemical stability, and biocompatibility represent a landmark on the development of multidisciplinary technologies. Lipid nanotubes (LNTs) are a unique class of lipid self-assembled structures, bearing unique properties such as high-aspect ratio, tunable diameter size, and precise molecular recognition. They can be obtained either by the action of external factors to already formed vesicles or spontaneously, the latter depending strongly on subtle molecular features. Here, we report on the spontaneous formation of supported lipid nanotubes of a particular type of glycolipid, ohmline, whose hydrophobic core displays remarkable asymmetry. The combination of bulk and surface-sensitive techniques indicates that below its main transition, ohmline displays an interdigitated gel phase, likely driven by the unique asymmetry in its hydrophobic core. Enhanced order packing by interdigitation favors the formation of ohmline nanotubes in agreement with chiral-based models of nanotube formation. The findings presented in this work call for additional studies to link lipid molecular structure-assembly relationships, whose understanding is relevant for the controlled design of lipid nanotubes networks in particular and controlled design of soft-matter nanomaterials in general.

Recent Progress of pH-Responsive Peptides, Polypeptides, and Their Supramolecular Assemblies for Biomedical Applications

Peptides and polypeptides feature a variety of active functional groups on their side chains (including carboxylic acid, hydroxyl, amino, and thiol groups), enabling diverse chemical modifications. This versatility makes them highly valuable in stimuli-responsive systems. Notably, pH-responsive peptides and polypeptides, due to their ability to respond to pH changes, hold significant promise for applications in cellular pathology and tumor targeting. Extensive researches have highlighted the potentials of low pH insertion peptides (pHLIPs), peptide-drug conjugates (PDCs), and antibody-drug conjugates (ADCs) in biomedicine. Peptide self-assemblies, with their structural stability, ease of regulation, excellent biocompatibility, and biodegradability, offer immense potentials in the development of novel materials and biomedical applications. We also explore specific examples of their applications in drug delivery, tumor targeting, and tissue engineering, while discussing future challenges and potential advancements in the field of pH-responsive self-assembling peptide-based biomaterials.

Self-Assembled Molecular Fibers Aligned by Compression in Water

Molecular self-assembly has attracted much attention as a potential approach for fabricating nanostructured functional materials. To date, energy-efficient fabrication of nano-objects such as nanofibers, nanorings, and nanotubes is achieved using well-designed self-assembling molecules. However, the application of molecular self-assembly to industrial manufacturing processes remains challenging because regulating the positions and directions of self-assembled products is difficult. Non-covalent molecular assemblies are also too fragile to allow mechanical handling. The present work demonstrates the macroscopic alignment of self-assembled molecular fibers using compression. Specifically, the macroscopic bundling of self-assembled nanofibers is achieved following dispersion in water. These fiber bundles can also be chemically crosslinked without drastic changes in morphology via trialkoxysilyl groups. Subsequently, vertically oriented porous membranes can be produced rapidly by slicing the bundles. This technique is expected to be applicable to various functional self-assembled fibers and can lead to the development of innovative methods of producing anisotropic nanostructured materials.

Molecular dynamics simulation in tissue engineering

Introduction

In tissue engineering, the interaction among three primary elements, namely cells, material scaffolds, and stimuli, plays a pivotal role in determining the fate of cells and the formation of new tissue. Understanding the characteristics of these components and their interplay through various methodologies can significantly enhance the efficiency of the designed tissue engineering system. In silico methods, such as molecular dynamics (MD) simulation, use mathematical calculations to investigate molecular properties and can overcome the limitations of laboratory methods in delivering adequate molecular-level information.

Methods

The studies that used molecular dynamics simulation, either alone or in combination with other techniques, have been reviewed in this paper.

Results

The review explores the use of molecular dynamics simulations in studying substrate formation mechanism and its optimization. It highlights MD simulations' role in predicting biomolecule binding strength, understanding substrate properties' impact on biological activity, and factors influencing cell attachment and proliferation. Despite limited studies, MD simulations are considered a reliable tool for identifying ideal substrates for cell proliferation. The review also touches on MD simulations' contribution to cell differentiation studies, emphasizing their role in designing engineered extracellular matrix for desired cell fates.

Conclusion

Molecular dynamics simulation as a non-laboratory tool has many capabilities in providing basic and practical information about the behavior of the molecular components of the cell as well as the interaction of the cell and its components with the surrounding environment. Using this information along with other information obtained from laboratory tools can ultimately lead to the advancement of tissue engineering through the development of more appropriate and efficient methods.

Reversing the Trend: Deciphering Self-Assembly of Unconventional Amphiphiles Having Both Alkyl-Chain and PEG

In the field of molecular self-assembly, the core of an assembly is always made up of hydrophobic moiety like a long alkyl chain, whereas the outer part has always been a hydrophilic moiety such as poly(ethylene glycol) (PEG), or charged species. Hence, reversing the trend to manifest self-assembled structures with a PEG core and a surface consisting of alkyl chains in aqueous system is incredibly challenging. Herein, we architected a unique class of cationic bolaamphiphiles containing low molecular weight PEG and alkyl chains of different lengths. The bolaamphiphiles spontaneously form vesicles without external stimuli. These vesicles are unprecedented because PEG makes up the vesicle core, while the alkyl chains appear on the vesicles' exterior. Hence, this particular design reverses the usual trend of self-assembly formation. The vesicle size increases with the increase in alkyl chain-length. To our great surprise, we obtained large micelles for longest alkyl-chain amphiphile, which in turn act as a gemini amphiphile. The shift from a particular bolaamphiphile to gemini amphiphile with the variation of alkyl chain is also unexplored. Therefore, this specific class of self-assembled structure would compound a new paradigm in molecular self-assembly and supramolecular chemistry.

Molecular bowls for inclusion complexation of toxic anticancer drug methotrexate

We describe the preparation and study of novel cavitands, molecular bowls 16+ and 26+, as good binders of the anticancer drug methotrexate (MTX). Molecular bowls are comprised of a curved tribenzotriquinacene (TBTQ) core conjugated to three macrocyclic pyridinium units at the top. The cavitands are easily accessible via two synthetic steps from hexabromo-tribenzotriquinacene in 25% yield. As amphiphilic molecules, bowls 16+ and 26+ self-associate in water by the nucleation-to-aggregation pathway (NMR). The bowls are preorganized, having a semi-rigid framework comprising a fixed bottom with a wobbling pyridinium rim (VT NMR and MD). Further studies, both experimental (NMR) and computational (DFT and MCMM), suggested that a folded MTX occupies the cavity of bowls wherein it forms π-π, C-H-π, and ion pairing intermolecular contacts but also undergoes desolvation to give stable binary complexes (μM) in water. Moreover, a computational protocol is introduced to identify docking pose(s) of MTX inside molecular bowls from NMR shielding data. Both molecular bowls have shown in vitro biocompatibility with liver and kidney cell lines (MTS assay). As bowl 26+ is the strongest binder of MTX reported to date, we envision it as an excellent candidate for further studies on the way toward developing an antidote capable of removing MTX from overdosed cancer patients.

Harnessing Glycolipids for Supramolecular Gelation: A Contemporary Review

Within the scope of this review, our exploration spans diverse facets of amphiphilic glycolipid-based low-molecular-weight gelators (LMWGs). This journey explores glycolipid synthesis, self-assembly, and gelation with tailorable properties. It begins by examining the design of glycolipids and their influence on gel formation. Following this, a brief exploration of several gel characterization techniques adds another layer to the understanding of these materials. The final section is dedicated to unraveling the various applications of these glycolipid-based supramolecular gels. A meticulous analysis of available glycolipid gelators and their correlations with desired properties for distinct applications is a pivotal aspect of their investigation. As of the present moment, there exists a notable absence of a review dedicated exclusively to glycolipid gelators. This study aims to bridge this critical gap by presenting an overview that provides novel insights into their unique properties and versatile applications. This holistic examination seeks to contribute to a deeper understanding of molecular design, structural characteristics, and functional applications of glycolipid gelators by offering insights that can propel advancements in these converging scientific disciplines. Overall, this review highlights the diverse classifications of glycolipid-derived gelators and particularly emphasizes their capacity to form gels.

Reversible structural change of [Co2Fe2] complexes between diamagnetic hydrogen-bonded 1D chains and paramagnetic complexes within a layered structure of amphiphilic anions

The combination of amphiphilic ions and metal complexes may enable the construction of assemblies in which the assembly structure and electronic state of the metal complexes change concertedly. In this work, an alternating layered structure of [Co2Fe2] complexes and amphiphilic anions was constructed. In the crystal structure, [Co2Fe2] complexes and water molecules formed a hydrogen-bonded supramolecular one-dimensional (1D) chain in the hydrophilic layer. A reversible structural change between the 1D chain and discrete [Co2Fe2] complexes was found to occur concertedly with an electron transfer-coupled spin transition (ETCST) of the [Co2Fe2] complex and desorption/adsorption of water molecules.

Macronutrient and PFOS bioavailability manipulated by aeration-driven rhizospheric organic nanocapsular assembly

Ubiquitous presence of the extremely persistent pollutants, per- and polyfluoroalkyl substances, is drawing ever-increasing concerns for their high eco-environmental risks which, however, are insufficiently considered based on the assembly characteristics of those amphiphilic molecules in environment. This study investigated the re-organization and self-assembly of perfluorooctane sulfonate (PFOS) and macronutrient molecules from rhizospheric organic (RhO) matter induced with a common operation of aeration. Atomic force microscopy (AFM) with infrared spectroscopy (IR)-mapping clearly showed that, after aeration and stabilization, RhO nanocapsules (∼ 1000 nm or smaller) with a core of PFOS-protein complexes coated by "lipid-carbohydrate" layers were observed whereas the capsule structure with a lipid core surrounded by "protein-carbohydrate-protein" multilayers was obtained in the absence of PFOS. It is aeration that exerted the disassociation of pristine RhO components, after which the environmental concentration PFOS restructured the self-assembly structure in a conspicuous "disorder-to-order" transition. AFM IR-mapping analysis of faeces combined with quantification of component uptake denoted the decreased ingestion and utilization of both PFOS and proteins compared with lipids and carbohydrates when Daphnia magna were fed with RhO nanocapsules. RhO nanocapsules acted as double-edged swords via simultaneously impeding the bioaccessibility of hazardous PFOS molecules and macronutrient proteins; and the latter might be more significant, which caused a malnutrition status within merely 48 h. Elucidating the assembly structure of natural organic matter and environmental concentration PFOS, the finding of this work could be a crucial supplementation to the high-dose-dependent eco-effect investigations on PFOS.

Organic chiral nano- and microfilaments: types, formation, and template applications

Organic chiral nanofilaments are part of an important class of nanoscale chiral materials that has recently been receiving significant attention largely due to their potential use in applications such as optics, photonics, metameterials, and potentially a range of medical as well as sensing applications. This review will focus on key examples of the formation of such nano- and micro-filaments based on carbon nanofibers, polymers, synthetic oligo- and polypeptides, self-assembled organic molecules, and one prominent class of liquid crystals. The most critical aspects discussed here are the underlying driving forces for chiral filament formation, potentially answering why specific sizes and shapes are formed, what molecular design strategies are working equally well or rather differently among these materials classes, and what uses and applications are driving research in this fascinating field of materials science.

Facile Preparation of Carbohydrate-Containing Adjuvants Based on Self-Assembling Glycopeptide Conjugates

Carbohydrates are intriguing biomolecules possessing diverse biological activities, including immune stimulating capability. However, their biomedical applications have been limited by their complex and heterogeneous structures. In this study, we have utilized a self-assembling glycopeptide conjugate (GPC) system to produce uniform nanoribbons appending homogeneous oligosaccharides with multivalency. This system successfully translates the nontrivial structural differences of oligomannoses into varied binding affinities to C-type lectin receptors (CLRs). We have shown that GPCs could promote the CLR-mediated endocytosis of ovalbumin (OVA) antigen, and two mannotriose-modified peptides F3m2 and F3m5 exhibit potent activity in inducing antigen-presenting cell maturation, as indicated by increased CD86 and MHCII expression. In vivo studies demonstrated that GPCs, combined with OVA antigen, significantly enhanced OVA-specific antibody production. Specifically, F3m2 and F3m5 exhibited the highest immunostimulatory effects, eliciting both Th1- and Th2-biased immune responses and promoting differentiation of CD4+ and CD8+  T cells. These findings highlight the potential of GPCs as vaccine adjuvants, and showcase their versatility in exploiting the biological functions of carbohydrates.

Controlled assembly of photosensitizers through directional interactions for effective photooxidation

Despite the fact that effective photosensitizers (PSs) can be achieved through rational molecular design, controlling the hierarchical assemblies of individual PSs with distinct function and morphological nanoscopic architectures remains a challenge. Here, very ordered one-dimensional PS polymers and their hollow tubular structures are presented from aqueous assembly of organic PS-based di- or tri-blocked supramolecules. Di-blocked PSs were interdigitated into 1D fibrils, significantly quenching photooxidation. Meanwhile, tri-blocked PSs were tilted with respect to each other to generate hollow tubules, showing remarkable photo-activities as well as photo-stability, which are particularly suited for green chemistry due to their unusual rapid photo-oxidation.

Enhancement of Circularly Polarized Luminescence from Pulsating Nanotubules

Enhancing the dissymmetry factor (glum ) is a crucial issue in developing circularly polarized luminescence (CPL) materials. Herein, based on supramolecular self-assembly of diethyl l-glutamate-cyanodiarylethene (L-GC) in mixed solution of EtOH-H2 O with different water fraction, enhanced circularly polarized emission from pulsating nanotubules is realized. In the mixture of ethanol and water (30/70, v/v), L-GC self-assembles into roll-up-type dense nanotubes and shows l-CPL. Remarkably, by increasing the water fraction to 80% and 90%, the diameter of the roll-up nanotubes increases and the dissymmetry factor of the nanotubes is significantly enhanced from 6.9 × 10-3  (dense nanotubes) to 3.7 × 10-2 (loose nanotubes) because of the enhanced intermolecular interactions and more ordered supramolecular stacking when increasing the water fraction. An efficient way is provided here to realize the increase of the dissymmetry factor by only changing the composition of solvents.

Melamine-participant hydrogen-bonded organic frameworks with strong hydrogen bonds and hierarchical micropores driving extraction of nitroaromatic compounds

Enrichment and detection of trace pollutants in the real matrix are essential for evaluating water quality. In this study, benefiting from the good affinities of 1,3,6,8-tetra(4-carboxylphenyl)pyrene) (H4TBAPy) with itself and melamine (MA) respectively, the composite hydrogen-bonded organic frameworks (HOFs, MA/PFC-1), PFC-1 self-assembled by 1,3,6,8-tetra(4-carboxylphenyl)pyrene), were successfully constructed by the mild strategy of solvent evaporation at room temperature. Through a series of characterizations, such as Fourier transform infrared spectra, X-ray diffraction, thermal gravimetric analyses, and N2 adsorption-desorption, etc., the MA/PFC-1 was confirmed to be a stable and excellent material. In addition, it possessed high surface area, hierarchical micropores, strong hydrogen bonds, and rich function groups containing N and O heteroatoms, since the newly introduced MA could be another hydrogen bonding motif, as well as increased the polarity of reaction solvent. These advantages make MA/PFC-1 be an ideal coating material for solid phase microextraction (SPME). Satisfactory enrichment factors for nitroaromatic compounds (NACs) were got by the MA/PFC-1 fiber under the optimized conditions obtained by the control variables (extraction time of 60 min, extraction temperature of 80 °C, desorption time of 6 min, desorption temperature of 260 °C, pH value of 7, and stirring speed of 250 rpm). MA/PFC-1 was further used to develop an analytical method for NACs based on head-space SPME coupled with gas chromatography‒mass spectrometry (GC‒MS). The developed method with low limits of detection (4.30-20.83 ng L-1) and good reproducibility (relative standard deviations <8.6%). The excellent performance allowed the successful application of the developed method in the determinations of trace NACs in real water samples with recoveries of 80.1%-119%. This study proposed a mild approach to synthesize composite HOFs via doping MA and developed an environmentally friendly method for the precise determinations of NACs in the environment.

Stacked or Folded? Impact of Chelate Cooperativity on the Self-Assembly Pathway to Helical Nanotubes from Dinucleobase Monomers

Self-assembled nanotubes exhibit impressive biological functions that have always inspired supramolecular scientists in their efforts to develop strategies to build such structures from small molecules through a bottom-up approach. One of these strategies employs molecules endowed with self-recognizing motifs at the edges, which can undergo either cyclization-stacking or folding-polymerization processes that lead to tubular architectures. Which of these self-assembly pathways is ultimately selected by these molecules is, however, often difficult to predict and even to evaluate experimentally. We show here a unique example of two structurally related molecules substituted with complementary nucleobases at the edges (i.e., G:C and A:U) for which the supramolecular pathway taken is determined by chelate cooperativity, that is, by their propensity to assemble in specific cyclic structures through Watson-Crick pairing. Because of chelate cooperativities that differ in several orders of magnitude, these molecules exhibit distinct supramolecular scenarios prior to their polymerization that generate self-assembled nanotubes with different internal monomer arrangements, either stacked or coiled, which lead at the same time to opposite helicities and chiroptical properties.

Solution-based self-assembly synthesis of two-dimensional-ordered mesoporous conducting polymer nanosheets with versatile properties

Conducting polymers with conjugated backbones have been widely used in electrochemical energy storage, catalysts, gas sensors and biomedical devices. In particular, two-dimensional (2D) mesoporous conducting polymers combine the advantages of mesoporous structure and 2D nanosheet morphology with the inherent properties of conducting polymers, thus exhibiting improved electrochemical performance. Despite the use of bottom-up self-assembly approaches for the fabrication of a variety of mesoporous materials over the past decades, the synchronous control of the dimensionalities and mesoporous architectures for conducting polymer nanomaterials remains a challenge. Here, we detail a simple, general and robust route for the preparation of a series of 2D mesoporous conducting polymer nanosheets with adjustable pore size (5-20 nm) and thickness (13-45 nm) and controllable morphology and composition via solution-based self-assembly. The synthesis conditions and preparation procedures are detailed to ensure the reproducibility of the experiments. We describe the fabrication of over ten high-quality 2D-ordered mesoporous conducting polymers and sandwich-structured hybrids, with tunable thickness, porosity and large specific surface area, which can serve as potential candidates for high-performance electrode materials used in supercapacitors and alkali metal ion batteries, and so on. The preparation time of the 2D-ordered mesoporous conducting polymer is usually no more than 12 h. The subsequent supercapacitor testing takes ~24 h and the Na ion battery testing takes ~72 h. The procedure is suitable for users with expertise in physics, chemistry, materials and other related disciplines.

Role of supramolecular polymers in photo-actuation of spiropyran hydrogels

Supramolecular-covalent hybrid polymers have been shown to be interesting systems to generate robotic functions in soft materials in response to external stimuli. In recent work supramolecular components were found to enhance the speed of reversible bending deformations and locomotion when exposed to light. The role of morphology in the supramolecular phases integrated into these hybrid materials remains unclear. We report here on supramolecular-covalent hybrid materials that incorporate either high-aspect-ratio peptide amphiphile (PA) ribbons and fibers, or low-aspect-ratio spherical peptide amphiphile micelles into photo-active spiropyran polymeric matrices. We found that the high-aspect-ratio morphologies not only play a significant role in providing mechanical reinforcement to the matrix but also enhance photo-actuation for both light driven volumetric contraction and expansion of spiropyran hydrogels. Molecular dynamics simulations indicate that water within the high-aspect-ratio supramolecular polymers exhibits a faster draining rate as compared to those in spherical micelles, which suggests that the high-aspect-ratio supramolecular polymers effectively facilitate the transport of trapped water molecules by functioning as channels and therefore enhancing actuation of the hybrid system. Our simulations provide a useful strategy for the design of new functional hybrid architectures and materials with the aim of accelerating response and enhancing actuation by facilitating water diffusion at the nanoscopic level.

Large-Scale, Proteinaceous Nanotube Arrays with Programmable Hydrophobicity, Oleophilicity, and Gas Permeability

Nanotubular structures possess remarkable advantages in a broad range of areas, such as catalysis, sensing, microencapsulation, selective mass transport, filtration, and drug delivery. While the fields of carbon nanotubes and nanotubes made of several noncarbon materials (e.g., metals, oxides, semiconductors) have been progressing rapidly, proteinaceous nanotubes remained largely underexplored. Here, by retrofitting a template wetting approach with multiple silk-based suspensions, we present a rapidly scalable and robust technology for fabricating large arrays (e.g., 20 × 20 cm²) of well-aligned 1D nanostructures made of silk proteins. Benefiting from the polymorphic nature of silk, precise control over the size, density, aspect ratio, and morphology (tubes versus pillars) of silk nanostructures is achieved, which then allows for programmable modulation of the end materials' functions and properties (e.g., hydrophobicity, oleophilicity, and gas permeability). The silk nanotube arrays fabricated present great utility as antifouling coatings against marine algae and in oil extraction from oil-water mixtures.

Triple Thorpe-Ingold Effect in the Synthesis of 18-Membered C3 Symmetric Lactams Stacking as Endless Supramolecular Tubes

Three C₃ symmetric macrolactams were very efficiently cyclized from their linear precursors. Adequately located substituents are responsible for the enhancement of reactivity that is not observed in the unsubstituted parent. DFT calculations show that the properly folded cyclization precursor, the reactive conformer, is more populated than other conformers, leading to a decrease of free energy of activation. The crystal structure of the ring substituted with three very bulky esters indicates that tubular stacking is preserved.

An Inorganic-Organic Hybrid Framework Composed of Polyoxotungstate and Long-Chained Bolaamphiphile

Surfactants are functional molecules utilized in various situations. The self-assembling property of surfactants enables several molecular arrangements that can be employed to build up nanometer-sized architectures. This is beneficial in the construction of functional inorganic-organic hybrids holding the merits of both inorganic and organic components. Among several surfactants, bolaamphiphile surfactants with two hydrophilic heads are effective, as they have multiple connecting or coordinating sites in one molecule. Here, a functional polyoxotungstate inorganic anion was successfully hybridized with a bolaamphiphile to form single crystals with anisotropic one-dimensional alignment of polyoxotungstate. Keggin-type metatungstate ([H₂W₁₂O₄₀]^6-, H₂W₁₂) was employed as an inorganic anion, and 1,12-dodecamethylenediammonium (C₁₂N₂) derived from 1,12-dodecanediamine was combined as an organic counterpart. A simple and general ion-exchange reaction provided a hybrid crystal consisting of H₂W₁₂ and C₁₂N₂ (C₁₂N₂-H₂W₁₂). Single crystal X-ray structure analyses revealed a characteristic honeycomb structure in the C₁₂N₂-H₂W₁₂ hybrid crystal, which is possibly effective for the emergence of conductivity due to the dissociative protons of C₁₂N₂.

Management of Brain Cancer and Neurodegenerative Disorders with Polymer-Based Nanoparticles as a Biocompatible Platform

The blood-brain barrier (BBB) serves as a protective barrier for the central nervous system (CNS) against drugs that enter the bloodstream. The BBB is a key clinical barrier in the treatment of CNS illnesses because it restricts drug entry into the brain. To bypass this barrier and release relevant drugs into the brain matrix, nanotechnology-based delivery systems have been developed. Given the unstable nature of NPs, an appropriate amount of a biocompatible polymer coating on NPs is thought to have a key role in reducing cellular cytotoxicity while also boosting stability. Human serum albumin (HSA), poly (lactic-co-glycolic acid) (PLGA), Polylactide (PLA), poly (alkyl cyanoacrylate) (PACA), gelatin, and chitosan are only a few of the significant polymers mentioned. In this review article, we categorized polymer-coated nanoparticles from basic to complex drug delivery systems and discussed their application as novel drug carriers to the brain.

Molecular Geometry-Directed Self-Recognition in the Self-Assembly of Giant Amphiphiles

Three sets of polyoxometalate (POM)-based amphiphilic hybrid macromolecules with different rigidity in their organic tails are used as models to understand the effect of molecular rigidity on their possible self-recognition feature during self-assembly processes. Self-recognition is achieved in the mixed solution of two structurally similar, sphere-rigid T-shape-linked oligofluorene(TOF₄ ) rod amphiphiles, with the hydrophilic clusters being Anderson (Anderson-TOF₄ ) and Dawson (Dawson-TOF₄ ), respectively. Anderson-TOF₄ is observed to self-assemble into onion-like multilayer structures and Dawson-TOF₄ forms multilayer vesicles. The self-assembly is controlled by the interdigitation of hydrophobic rods and the counterion-mediated attraction among charged hydrophilic inorganic clusters. When the hydrophobic blocks are less rigid, e.g., partially rigid polystyrene and fully flexible alkyl chains, self-recognition is not observed, attributing to the flexible conformation of hydrophobic molecules in the solvophobic domain. This study reveals that the self-recognition among amphiphiles can be achieved by the geometrical limitation of the supramolecular structure due to the rigidity of solvophobic domains.

Topological Connection between Vesicles and Nanotubes in Single-Molecule Lipid Membranes Driven by Head-Tail Interactions

Lipid nanotube-vesicle networks are important channels for intercellular communication and transport of matter. Experimentally observed in neighboring mammalian cells but also reproduced in model membrane systems, a broad consensus exists on their formation and stability. Lipid membranes must be composed of at least two molecular components, each stabilizing low (generally a phospholipid) and high curvatures. Strong anisotropy or enhanced conical shape of the second amphiphile is crucial for the formation of nanotunnels. Anisotropic driving forces generally favor nanotube protrusions from vesicles. In this work, we report the unique case of topologically connected nanotubes-vesicles obtained in the absence of directional forces, in single-molecule membranes, composed of an anisotropic bolaform glucolipid, above its melting temperature, T_m. Cryo-TEM and fluorescence confocal microscopy show the interconnection between vesicles and nanotubes in a single-phase region, between 60 and 90 °C under diluted conditions. Solid-state NMR demonstrates that the glucolipid can assume two distinct configurations, head-head and head-tail. These arrangements, seemingly of comparable energy above the T_m, could explain the existence and stability of the topologically connected vesicles and nanotubes, which are generally not observed for classical single-molecule phospholipid-based membranes above their T_m.

Chiral three-dimensional supramolecular assemblies: colloidal onions, cubosomes, and hexosomes

Amphiphilic molecules can self-assemble in solution into a variety of supramolecular assemblies, ranging from simple micelles, ribbons, and tubes to complex cubosomes with bicontinuous cubic nanostructures. It is well known that the self-assembly of chiral building blocks into one-dimensional (1D) twisted fibers, helical ribbons, and tubes enables chiral transfer from the molecular scale to super-assemblies. In this study, we investigate the chirality of three-dimensional (3D) supramolecular assemblies, such as colloidal onions, cubosomes, and hexosomes, formed from the same chiral heteroclusters. Unlike supramolecular 1D helical ribbons, these assemblies do not have chiral external shapes or chiral internal nanostructures, but they do exhibit circular dichroism, suggesting that they are chiral. Structural studies revealed that the ordered arrangement of the chiral units in curved superstructures is the origin of the supramolecular chirality of these 3D assemblies. Therefore, this study provides insights for enriching the diversity and complexity of supramolecular chiral assemblies.

Mesoporous multi-shelled hollow resin nanospheres with ultralow thermal conductivity

Hollow nanostructures exhibit enclosed or semi-enclosed spaces inside and the consequent features of restricting molecular motion, which is crucial for intrinsic physicochemical properties. Herein, we developed a new configuration of hollow nanostructures with more than three layers of shells and simultaneously integrated mesopores on every shell. The novel interior configuration expresses the characteristics of periodic interfaces and abundant mesopores. Benefiting from the suppression of gas molecule convection by boundary scattering, the thermal conductivity of mesoporous multi-shelled hollow resin nanospheres reaches 0.013 W m-1 K-1 at 298 K. The designed interior mesostructural configuration of hollow nanostructures provides an ideal platform to clarify the influence of nanostructure design on intrinsic physicochemical properties and propels the development of hollow nanostructures.

Temperature and oxidation-sensitive dioleoylphophatidylethanolamine liposome stabilized with poly(ethyleneimine)/(phenylthio)acetic acid ion pair

Temperature and oxidation-sensitive liposomes were prepared by stabilizing dioleoylphosphatidylethanolamine (DOPE) bilayers with the ion pair of poly(ethyleneimine)/(phenylthio)acetic acid (PEI/PTA). An upper critical solution temperature (UCST) behavior was observed when PEI/PTA ion pair was suspended in an aqueous solution. It was observed that the UCST increased with increasing PTA content. The ion pair was self-assembled into nanospheres owing to its amphiphilic property which was confirmed by transmission electron microscopy. The FT-IR spectroscopic spectrum showed that the ion pair formed a salt bridge between the amino group and the carboxyl group and the PTA content in the ion pair was readily oxidized by H₂O₂. Further, DOPE liposomal membranes could be stabilized with PEI/PTA ion pair. Due to the amphiphilic property, the ion pair played a role as a stabilizer for the formation of DOPE liposomes. The liposome released its payload in a temperature-responsive manner, possibly because when the temperature is raised, the ion pair loses its amphiphilic property and can be detached from the liposomal membrane. The liposome was also oxidation-responsive in terms of release, possibly because the amphiphilic property of the ion pair disappears when the PTA is oxidized.

Fabrication, modification and application of lipid nanotubes

The potential application of high aspect-ratio nanomaterials motivates the development of the fabrication and modification of lipid nanotubes(LNTs). To date, diverse fabricate processes and elaborate template procedures have produced suitable tubular architectures with definite dimensions and complex structures for expected functions and applications. Herein, we comprehensively summarize the fabrication of LNTs in vitro and discuss the progress made on the micro/nanomaterials fabrication using LNTs as a template, as well as the functions and possible application of a wide range of LNTs as fundamental or derivative material. In addition, the characteristics, advantages, and disadvantages of different fabrication, modification methods, and development prospects of LNTs were briefly summarized.

Electrostatic Control of Shape Selection and Nanoscale Structure in Chiral Molecular Assemblies

How molecular chirality manifests at the nano- to macroscale has been a scientific puzzle since Louis Pasteur discovered biochirality. Chiral molecules assemble into meso-shapes such as twisted and helical ribbons, helicoidal scrolls (cochleates), or möbius strips (closed twisted ribbons). Here we analyze self-assembly for a series of amphiphiles, C _n -K, consisting of an ionizable amino acid [lysine (K)] coupled to alkyl tails with n = 12, 14, or 16 carbons. This simple system allows us to probe the effects of electrostatic and van der Waals interactions in chiral assemblies. Small/wide-angle X-ray scattering (SAXS/WAXS) reveals that at low pH, where the headgroups are ionized (+1), C₁₆-K forms high aspect ratio, planar crystalline bilayers. Molecular dynamics (MD) simulations reveal that tilted tails of the bilayer leaflets are interdigitated. SAXS shows that, with increasing salt concentration, C₁₆-K molecules assemble into cochleates, whereas at elevated pH (reduced degree of ionization), helices are observed for all C _n -K assemblies. The shape selection between helices and scrolls is explained by a membrane energetics model. The nano- to meso-scale structure of the chiral assemblies can be continuously controlled by solution ionic conditions. Overall, our study represents a step toward an electrostatics-based approach for shape selection and nanoscale structure control in chiral assemblies.

New Carbamates and Ureas: Comparative Ability to Gel Organic Solvents

Two series of novel amphiphilic compounds were synthesized based on carbamates and ureas structures, using a modification of the synthesis methods reported by bibliography. The compounds were tested for organic solvent removal in a model wastewater. The lipophilic group of all compounds was a hexadecyl chain, while the hydrophilic substituent was changed with the same modifications in both series. The structures were confirmed by FT-IR, NMR, molecular dynamic simulation and HR-MS and their ability to gel organic solvents were compared. The SEM images showed the ureas had a greater ability to gel organic solvents than the carbamates and formed robust supramolecular networks, with surfaces of highly interwoven fibrillar spheres. The carbamates produced corrugated and smooth surfaces. The determination of the minimum gelation concentration demonstrated that a smaller quantity of the ureas (compared to the carbamates, measured as the weight percentage) was required to gel each solvent. This advantage of the ureas was attributed to their additional N-H bond, which is the only structural difference between the two types of compounds, and their structures were corroborated by molecular dynamic simulation. The formation of weak gels was demonstrated by rheological characterization, and they demonstrated to be good candidates for the removal organic solvents.